Simplify CPP CI with generated files

[nikobockerman]

Replace the complex conan profiles and CMakeUserPresets.json with one python script that generates those with contents specific for the one matrix variant. This removes the need for complex and error-prone inherited presets with environment variables, Jinja code in conan presets, environment variable logic between CMake preset and conan profile.

[Copilot]

Pull request overview

This PR simplifies the C++ CI pipeline by replacing the previously committed, templated Conan profiles and CMakeUserPresets.json with a single Python generator that emits concrete, per-matrix CI configuration files at workflow runtime.

Changes:

• Add a Python generator to produce solvers/cpp/CMakeUserPresets.json, solvers/cpp/conan-profile-ci, and solvers/cpp/ci.env for the active matrix entry.
• Update the C++ CI workflow to call the generator and run cmake/ctest directly (removing the lukka/run-cmake workflow-preset usage).
• Remove the old .github/files/* preset/profile templates and stop copying them in the setup action.

Reviewed changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
.gitignore	Ignore newly generated CI-only files under solvers/cpp/.
.github/workflows/cpp-build-test-run.yaml	Generate and consume per-matrix C++ CI config; switch to direct cmake build/test invocation.
.github/scripts/generate-cpp-ci-config.py	New generator for CMake user presets, Conan host profile, and sanitizer runtime env exports.
.github/files/conan-profile-gcc-libstd++-for-clang	Remove old templated Conan profile (replaced by generator).
.github/files/conan-profile-clang-with-libc++-sanitizers	Remove old templated Conan profile (replaced by generator).
.github/files/conan-profile-clang-with-libc++	Remove old templated Conan profile (replaced by generator).
.github/files/conan-profile-clang-with-hardened-libc++	Remove old templated Conan profile (replaced by generator).
.github/files/CMakeUserPresets.json	Remove old committed CI preset bundle (replaced by generator).
.github/actions/cmake-project-setup/action.yaml	Stop copying preset/profile templates; action now focuses on CMake/Conan/sccache setup.

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[Copilot]

Pull request overview

Copilot reviewed 8 out of 9 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

.github/workflows/cpp-build-test-run.yaml:133

• The sanitizers job prepends ${HOMEBREW_PREFIX}/opt/llvm/bin to GITHUB_PATH, but the Homebrew setup action installs llvm@${LLVM_MAJOR_VERSION} (versioned formula). On runners without the unversioned llvm formula, this path won’t exist and tools like llvm-symbolizer won’t be found.

Use the versioned prefix (or brew --prefix) so the path matches the installed LLVM version.

        run: echo "${HOMEBREW_PREFIX}/opt/llvm/bin" | tee -a "${GITHUB_PATH}"